Send to another service¶

The http service posts each message with a body that you write as a template. So it can reach any service that accepts an HTTP request. Find the recipe for your service below, and copy it under notify.

The body is a Go template. The template gets these values and functions:

• .Title and .Body: the title of the message, such as "2 new devices on 192.0.2.0/24", and its text, with one change on each line.
• .ScanID: the scan that the changes came from. It is 0 for a test.
• .Events: each change, with .Kind, .DeviceID, .Device and .Change.
• json: writes a value as JSON, with quotes and escapes. Use it for every value in a JSON body, as {{ json .Title }}. Device names can contain quotes, and the body contains line breaks.
• truncate: cuts a string to a number of characters and adds … at the end, as {{ .Body | truncate 2000 | json }}. A message lists up to 20 changes. Long device names can make it longer than the limit of a service. The service then returns an error.

Jocasta sends the body as application/json, unless headers sets a different Content-Type. When Jocasta starts, it renders the template with two sample messages. One sample has a change. The other is the test message, which has no change. If the template does not parse, or its output is not valid JSON, Jocasta reports the problem and does not start.

A device gives its own name. So its name can contain text that a chat service reads as a mention, such as @everyone, or as formatting. The Slack, Telegram, Gotify, Pushover and Apprise recipes send plain text. Discord has no plain-text mode. So its recipe turns mentions off, but a device name can still show with formatting.

Discord, with the webhook URL from the Integrations settings of the channel:

discord:
  http:
    url: "https://discord.com/api/webhooks/<id>/<token>"
    body: '{"content": {{ printf "%s\n%s" .Title .Body | truncate 2000 | json }}, "allowed_mentions": {"parse": []}}'

Slack, with an incoming webhook URL. The message goes in a plain_text block, which Slack shows as it is. The recipe also sends the title as text, which Slack shows in its notifications:

slack:
  http:
    url: "https://hooks.slack.com/services/<path>"
    body: '{"text": {{ json .Title }}, "blocks": [{"type": "section", "text": {"type": "plain_text", "text": {{ printf "%s\n%s" .Title .Body | truncate 3000 | json }}}}]}'

Telegram, with the token of a bot and the chat to post in:

telegram:
  http:
    url: "https://api.telegram.org/bot<token>/sendMessage"
    body: '{"chat_id": "<chat id>", "text": {{ printf "%s\n%s" .Title .Body | truncate 4096 | json }}}'

Gotify, with the token of an application:

gotify:
  http:
    url: "https://gotify.example.com/message"
    headers:
      X-Gotify-Key: "<app token>"
    body: '{"title": {{ json .Title }}, "message": {{ json .Body }}, "priority": 5}'

Pushover, with the token of an application and your user key:

pushover:
  http:
    url: "https://api.pushover.net/1/messages.json"
    body: '{"token": "<app token>", "user": "<user key>", "title": {{ json .Title }}, "message": {{ .Body | truncate 1024 | json }}}'

For email, SMS, Microsoft Teams, Signal and many more, run an Apprise API server next to Jocasta. In Apprise, save the Apprise URLs of the services under a key. Then post to that key:

apprise:
  http:
    url: "http://apprise.example.com:8000/notify/jocasta"
    body: '{"title": {{ json .Title }}, "body": {{ json .Body }}}'

Home Assistant, n8n and Node-RED accept any JSON, so they use the webhook service. For Home Assistant, add an automation with a webhook trigger. Then set the url of a webhook destination to the webhook of that automation. Home Assistant does not check the signature, but you must still set a secret. The automation reads the message as trigger.json.title and trigger.json.message. It reads each change under trigger.json.events.

home_assistant:
  webhook:
    url: "http://homeassistant.local:8123/api/webhook/<webhook id>"
    secret: "change-me"